Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. The description adds meaningful behavioral detail beyond the annotations by explaining zero-filling, daily entry granularity, and the cumulative running total, though it does not discuss auth or rate limits.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is compact and front-loaded, stating the core data first and then adding the zero-fill and entry-shape details. Every clause contributes useful information without repetition.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

There is no output schema, but the description adequately explains the return shape: one entry per calendar day, from the first listing to today, each containing added and cumulative running total. Combined with the fully documented single optional parameter, this is complete for a read-only stats tool.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the range parameter's meaning and allowed values are already fully documented in the schema. The description does not add parameter-specific guidance beyond describing the default full-series shape, making the baseline score appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific resource and scope: active listings added per UTC day, zero-filled, one entry per calendar day, with added and cumulative running total. It is clear what the tool returns, but it does not explicitly differentiate itself from sibling tools such as get_stats.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Usage is implied by the phrase 'the zero-filled series behind the public /stats page,' which suggests a reporting context. However, it gives no explicit when-to-use guidance, when-not-to-use guidance, or named alternatives among the siblings.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.